A regulatory floodway runs through the village
Start with what a point sample of the flood maps would never have caught. Tested as polygons against the village boundary on effective panel set 36059C, the National Flood Hazard Layer returns 47 polygons wholly inside the village: 19 mapped as minimal-hazard Zone X, 12 at the 0.2-percent annual chance, 11 as Zone AE, and five as Zone AE sub-typed FLOODWAY. Widening to polygons that intersect the boundary adds two more floodway polygons and an unnumbered Zone A with no base flood elevation published. A regulatory floodway is the tightest designation the National Flood Insurance Program applies: substantial improvement, an addition or an elevation project inside one generally requires an engineer's no-rise certification. The zone changes from street to street, and the reliable answer is the parcel lookup at the FEMA Map Service Center. Note also that the 0.2-percent Zone X mapping is the 500-year floodplain, not an absence of hazard.
Three places share the name and two of them have no government
The 2020 census place-by-county file lists Valley Stream village as an INCORPORATED PLACE, GEOID 3676705, and lists North Valley Stream (3653748) and South Valley Stream (3669892) as separate census designated places, which by definition have no village government. An address in one of those two is outside the village's jurisdiction, and the office that holds its records is not village hall; an address inside the village line is the village building department's to permit and to certify. No certificate search procedure, fee or turnaround is published on the primary sources checked. Whether the village registers rental units, and on what terms, is a question for the village clerk.
Which sewer row applies, and to whom
The county health department's summary of sewer districts by community gives Valley Stream a row whose local sewer authority is Nassau County Department of Public Works, carrying no asterisk and appearing nowhere on the not-publicly-sewered list. The name trap matters here: North Valley Stream has its own separate row on the same document, and South Valley Stream has no row at all. Reading a status off the wrong row is an easy mistake. Two limits attach to the document however it is read - nothing on its face carries a date and the server sends no last-modified header, so how current it is cannot be established; and a community's presence in a collection district says nothing about whether a particular house was tied in or left on a cesspool. The county publishes an address-level sewer service check for exactly this. The Sewage Treatment Master Plan page names county facilities without mapping service areas, so no receiving plant is named here.
Nearly ten thousand homes built before 1960
The 2020-2024 American Community Survey counts 12,957 housing units in the village: 3,843 from 1939 or earlier, 2,352 from the 1940s and 3,421 from the 1950s - 9,616 from before 1960. The median year built is 1951. In stock of that age the lateral from the house to the sewer main is the homeowner's pipe, and its condition is a cost question rather than a village one. 9,857 units are detached, 1,695 sit in two-unit buildings and 530 in buildings of 50 or more; the 20 mobile homes counted carry a margin of 24 and are indistinguishable from zero. Of 12,340 occupied units, 9,710 are owner-occupied and 2,630 rented, the median value is $616,100 and the population is 40,315. A three-decade spread across a village this size means wiring method, waste stack material and service size are not uniform: pre-war plaster and cast iron, wartime building and 1950s tract methods all appear in the counts, though the tables give no geography for where each sits.
The two-family question
Those 1,695 units in two-unit buildings change the scope of a purchase. A legal two-family has to answer for the rating of what divides the units and what caps the cellar, an escape route out of each bedroom, separate metering, and whether the certificate on file at village hall describes what is standing. Where a basement has been fitted out as a separate unit, that certificate either covers it or does not: a second kitchen, a sleeping room without a compliant window, ceiling height and a separate entry are what it would have to describe.
Oil heat at scale, and a register that misses houses
Fuel oil or kerosene heats 2,792 of the village's occupied units, with a solar count of 56 that carries a margin of 88 and so means nothing. State spill records filed under the locality string Valley Stream run to 1,146 incidents, 1,051 petroleum, including 538 number 2 fuel oil and 144 gasoline; 426 are sourced to a private dwelling and 392 rows are both number 2 fuel oil and a private dwelling (NYSDEC spill incidents). The locality field is postal, not municipal, so read those as indicative. The state bulk storage register holds 26 records for Valley Stream, 16 petroleum and 10 chemical - a commercial register, which is why a residential tank in a back garden will not be on it. Tank documentation belongs in the contract.
Water supply, the plans that do not cover the village, and the trains
No community water system named for Valley Stream appears on the state health department's Nassau public water system contacts, though five other Nassau village systems are named on it; county-wide the county reports 46 public water systems and approximately 500 private wells. No state recovery plan covering the village itself was found: the South Valley Stream plan addresses North Woodmere and Mill Brook and describes its own community as bordered to both the north and east by the Village of Valley Stream (South Valley Stream NYRCR plan, PDF). Two Long Island Rail Road stations, Valley Stream and Gibson, both fall inside the village boundary, both on the Far Rockaway branch, fare zone 4, both with an accessibility field of FULL (MTA rail stations); one branch name per station under-describes a junction, and that field is a data entry rather than a site condition.